Conductor loaded resonator filters with wide spurious free stop band

A new configuration of conductor loaded resonator filters using two different sized conductor loaded resonators is presented. The spurious performance of the conductor loaded resonator filters are significantly improved. A rigorous mode matching method is used to compute the resonant frequency, unloaded Q and the field of the resonant mode of the conductor ( solid or ring) loaded resonators. The coupling coefficients between two resonators are computed using small aperture theory by Levy´s approach. An 8-pole elliptic function filter is designed, constructed and tested. Experimental results verify the theory.